Clutch mechanism



March 2, 1937. R. P. L Ewls 2,072,117

' CLUTCH MECHANISM Filed Sept. 5, 1955 2 sheets-sheet 1 4 .ILE

March 29 1937. R. P. LEWIS CLUTCH MECHANISM Filed Sept. 5, 1935 2 Sheets-Sheet 2 Patented Mar. 2, 1937 PATENT oFFlcE 2,072,117 CLUTCH MEcHANrsM Robert P. Lewis, Toledo, Ohio, assigner to Spicer Manufacturing Corporation, Toledo, Ohio, a

corporation of Virginia Application September 5,

9 Claims.

The present invention relates to mechanisms for transmitting power from a driving member to a driven member, and it is particularly concerned with improved mechanisms for picking up loads without shock, and although it is particularly useful in automatic clutches, it may be also advantageously employed in manually operable clutches. In speed responsive clutches of the centrifugal type, for instance the clutch shown in Vail Pat- 0 ent No, 1,822,716, clutch engagement is normally. solely dependent upon speed. It has been found that in certain commonly employed automotive drives, by reason of the nature of the transmission or free wheeling or other driven units, excessive lost motion or backlash exists between the driven clutch shaft and the vehicle wheels, with the result that if the vehicle is equipped with a centrifugal clutch, and the engine or other prime mover4 is suddenly accelerated the lost motion or backlash is almost instantaneously taken up and an-objectionable noise commonly termed a clunk occurs.

In my copending application Serial No. 706,109, filed January 10, 1934, I have disclosed a mechanism which may be applied to centrifugal clutches and which efficiently takes up any lost motion in the driven assembly connected to an automatic or manual clutch, and it is a primary object of present invention to provide a mechanism having all of the desirable operating characteristics of the mechanisms shown in my aforesaid copending application, and to also generally refine and improvethose constructions.

It is a further object of my invention to provide power transmitting mechanisms for use in clutches and the like, and which will respond to a predetermined acceleration and transmit torque between the driving and driven shafts, and yet which may be readily rendered inactive.

A further object is to devise a power transmitting mechanism which is responsive to acceleration to transmit torque between driving and driven members, and which is provided with resilient means for preventing the magnitude of the torque transmitted thereby from exceeding a predetermined value.

Further objects of my invention will become apparent as the specification proceeds in connection with the annexed drawings, and from the appended claims.

In the drawings:

Figure 1 is a longitudnal sectional view of an automatic clutch embodying the power transmitting mechanism of my invention and the parts are 55 illustrated in automatic disengaged condition.

1935, Serial No. 39,327

Figure 2 is a fragmental sectional view of the inertia ring assembly shown in Figure l, and illustrates the cooperation of the actuating pins with the slots in the ring support.

Figure 3 is a fragmental sectional View of the inertia ring and its support, and illustrates one of the stop assemblies for limiting angular movements of the inertia ring.

Figure 4 is a sectional view somewhat similar to Figure l, illustrating a modified form of the invention.

Figure 5 is a fragmental sectional view of the modification shown in Figure 4, and it illustrates one of the actuating pin assemblies.

Figure 6 is a fragmental sectional View illustrating a further modified form of my invention.

Figure 7 is a fragmental sectional View of the modiiicationillustrated in Figure 6 and shows one of the actuating pin assemblies.

Figure 8 also is a fragmental sectional view of the modication of the invention shown in Figure 6 and it shows one of the stop pin assemblies.

With continued reference' to the drawings, wherein 4like reference characters have been employed to designate like parts throughout the several views thereof, I have illustrated my invention as being applied to a centrifugally operable clutch, but it is to be understood that if desired it might be used with any other type of speed responsive or solely manual operable clutch without departing from the spirit of my invention.

With continued reference toFigure 1, the automatic clutch comprises a driving shaft I, a driven shaft 2, a flywheel 4I to which is secured a cover or housing 6, and a pressure plate 'I, hereinafter termed the automatic plate, is disposed within cover 6 and is mounted for synchronous rotation therewith by means of driving lugs 8.

A driven member, designated generally at II, and having fictional facings I2 secured thereto, is splined to shaft 2 and is adapted to be frictionally gripped between plate 1 and the ywheel face. A reaction plate I3 is disposed adjacent plate 1 and they are l.urged toward each other by against the action of springs I6 by means of a.

plurality of levers I1, carried on cover 6 by brack-V ets I8, and their outer ends cooperate"with nut and washer assemblies I9 carried by bolts 20.

Bolts 26 are lfrictionally fitted into apertures in.v

plate I3.

Levers I1 cooperate with a throwout assembly designated generally at 22, and which is mounted for sliding movement on a support 23 secured to a clutch housing 24 in any well known manner (not shown). Axial movement of throwout assembly 22 is effected by means of a fork 25, which is secured to a throwout shaft 26.

Plate 'I is actuated by means of a plurality of centrifugally operable weight members designated generally atl 21, which have lever portions extending through apertures in plate I3 and carry offset portions 28, which are normally clamped between plate I3 and the bottomof recesses located in plate 1 by the holdback springs, when the prime mover associated with the driving shaft is operated at or below a predetermined idling speed. Weights 21 are adapted to rock outwardly about fulcrums 29 provided on offset portions 28, to thereby force plates 1 and I3 away from each other against the action of the holdback springs when driving shaft I is accelerated to speeds substantially in excess of idling speed.

The clutch just described is more fully ldisclosed in copending application Serial No. 676,567,

filed June 19, 1933, and as the structural details.

thereof form no part of the present invention, it will not be further described other than to point out that shaft 26 is normally maintained in the position shown in Figure 1 by means of a latch or the like for holding the parts in automatic idling condition shown when the engine is operating at idling speed or is stopped. The latch may be released if desired to allow spring I6 to force the plates into engagement when the engine is stopped.

When the engine is accelerated with shaft 26 disposed in the latched position as shown in Figure 1, weights 21 rock outwardly about their fulcrums 'and bring the plates into engagement.

Shaft 26 may be rocked in a counterclockwise direction, from the position shown in Figure 1 into disengaging position, so as to move reaction plate I3 to the right and carry plate 1 with it sufficiently far so that weights 21 are ineffective to engage the plates. Shaft 26 may be allowed to rock clockwise and allow springs I6 to engage the clutch even when the engine is stopped.

Mounted for limited rocking or limited rotative movement with respect to the driving and reaction plate assembly, and adapted to cooperate with the inner edge of the driven facing I2, is a comparatively narrow friction plate 45, which I will hereinafter term an inertia ring, because it is responsive .to acceleration-induced inertia forces to engage the driven member.

Ring 45 is slidably mounted on the periphery of a ring-like support 46, which is secured to reaction plate I3 -by means of rivets 41 or the like. Ring 46 is provided with a plurality of actuating pin slots 49 and a plurality of stop pin slots 5I. Slots 49 are inclined, and as shown in Figure 2 the slots assume a helix angle of approximately 65 degrees. .A plurality of actuating pins 53 are secured in apertures in ring 45 in any suitable manner and cooperate with the walls of lslots 49.

axis of the mechanism, and cooperate with a plurality ,of stop pins 54 which are secured in ring 45. angular movement upon support 46 and its range of movement is determined by the width of stop pin slots 5I. As ring 45 undergoes rocking movement, actuating pins 53 cooperate with the walls of slots 49 to advance the ring toward facing I2, or to retract toward the reaction plate, depending upon the accelerating forces and the direction of power transmission.

With the parts rotating at normal engine idling A speed, in the direction indicated by the arrows in Figures 1, 2, and 3, the clutch is fully disengaged, as seen in Figure 1. When shaft` I is given an acceleration of predetermined magnitude, ring 45, by virtue of its inertia, tends to remain at idling speed or lags behind .plate 1, with, the result that actuating pins 53 are forced into engagement with the walls of slot 49 and the reaction set up advances ring 45 toward the flywheel and into engagement with facing I2. Con- Ringv 45 is accordingly .mounted for versely, when shaft -I and plates 1 are suddenlyim decelerated, the angular momentum of ring 45l opposes the decelerating action, and pins 53 cooperate with slots 49 and tend to retract the ring and restore it to the position illustrated in Figure 1.

When shaft I is accelerated as just described, and ring 45 is advanced into engagement with facing I2, the frictional coupling thus established tends to retard rotation of ring 45, and this reaction causes pins 53 to cam ring 45 with greater force toward facing I2, with the result that ring 45 undergoes a self-energizing or servo engaging action. As ring 45 is limited in its movement by stop pins 54, it can only advance a predetermined distance toward the flywheel under either the accelerating or servo actions.

With ring 45 engaged with facing I2 in response to the accelerating yoperation just described, a power transmitting connection of comparatively low torque capacity is established between shafts I and 2, and when shaft I attains a higher predetermined speed in excess of idling speed, weights 21 rock outwardly about their ful- .wardly in response to centrifugal force, reaction plate I3 moves to the right away from the flywheel, and hence actuation of the automatic plate does not in any way tend to cause ring to exert further pressure upon facing I2. When shaft I reaches a predetermined higher speed, weights 21 rock out into their final position and bring 'their stop faces 4I into engagement with flange 42 of reaction plate I3. Thereafter further acceleration of driving shaft I is accordingly ineffective to build up further pressure in the clutch.

Assuming that the v.flywheel is operating at idling speed and the engine is only given a moderate acceleration, ring 45 will still manifest an inertia effect, but it will be of such small magmtude that it will not engage facing I2, and thereafter, if the engine is further accelerated, weights 21 will bring the plates into engagement as just described. Although, in this instance plate 1 is the only power transmitting medium, because of the low rate of acceleration, an acceleration of this character produces a low torque engagement of plate 1, 'and the backlash in the driven assembly is nevertheless taken up quietly and smoothly'.

With the clutch fully engaged as just described,

and the engine is decelerated, with the driven shaft tending to drive the drivingshaft, as soon as facing I2 starts to slip with respect to plate 1 and ring 45, actuating pins 53 will cooperate with the other walls of slots 49 to exert a self-deenergizing effect upon ring 45 and bring it into disengagement. Ring 45 accordingly manifests no tendency to drag upon automatic disengagement of the clutch.

With the clutch fully engaged as just described, and it is desired to disengage'the clutch, shaft 26 may be rocked anti-clockwise to move the throwout assembly to the left, and through levers I1, to move plate I3 to the right, and thereby carry plate 1 out of engagement with facing I2; notwithstanding the fact that weights 21 may remain in engagement with flange 4I of plate I3. Be-

cause of the stop pins provided on ring 45, the

latter can not remain in a position where it will engage facing I2, and therefore the clutch may be cleanly disengaged without drag.

Referring now to Figures 4 and 5, I have illustrated a modified form of my invention wherein the engaging forces applied to ring 45a in response to acceleration are limited to a predetermined magnitude by the use of springs. With continued reference to these figures, ring 45a is mounted for angular rocking movement on a support 46a in a manner similar to the ring of the first form of the invention. the support 46a is provided with a plurality of slots each having an inclined wall 6I, and a wall 62 which is disposed normal to the face of. the.

plate. Secured in position between the support 46aand reaction plate I3 are a plurality of spring members 63, having inclined resilient fingers 64, eachof which provides a pin actuating face normally disposed substantially parallel to wall 6I. A plurality of actuating pins 65, corresponding in number to the slots in support'45a, are secured in ring 45a and cooperate with walls 6I and springs 64, as indicated in Figure 5.

When driving shaft I is given a sudden acceleration, ring 45a manifests a tendency to remain stationary, as was the case in the first form of the invention and in this instance ring 45a. causes pins 65 to react against springfingers 54, and by reason of the inclination thereof, pins 65 are acted upon so as to advance ring 45 into engagement with facing I2 and take up the backlash in the manner previously described. Upon engagement of ring 45a with facing I2, a self-energizing action is set up as was the case in the previously described form of the invention, but in this case, the torque capacity of the resulting slipping coupling is much lower, because pins 55 promptly assume the position illustrated in dotted lines in Figure 5, and cause spring fingers 64 to deect into the dotted line position, During the normal accelerating operation, ring 4501 is accordingly urged into engagement with facing I2 under a yielding pressure exactly equal to the tension of fingers 64 in their dotted line position. The pressure can not exceed this value because wall 62 of the recess in support 46a isrparallel to the direction of travel of the ring 45a and therefore can not apply engaging forces thereto. When' the parts assume the dotted line position shown in Figure 5, further angular rocking movement of ring 45a is arrested by reason of engagement of pins 65 with walls 62, and therefore in this form of the invention it is not necessary to employ stop pin assemblies as the actuating pins perform their function.

With ring 45al advanced in the manner just de- In this instance scribed, further acceleration of shaft I is operable to bring plate 1 into engagement with facing I2 as previously described, and if it is desired to declutch, this may be effected by rocking shaft 26 in the manner described in connection with the first form of my invention. With the clutch fully engaged as just described, decelaration of the engine is operable to effect automatic disengagement of plate 1 and when this has occurred or the pressure has decreased to such a value that a slipping drive is established between facing I2 and ring 45a and plate 1, with the driven shawt tending to drive the driving shaft, actuating pins 65 are promptly restored to their full line position illustrated in Figure 5 and which results in prompt disengagement of ring 45a from facing I2. It is therefore seen that when the self-energizing engaging operation is effected a resilient means automatically limits the pressure build-up, whereas when the self-de-ener- Iwall 6I with actuating pins 65. it is to be understood, however, that if desired wall 6I of support 46a may take the form of a spring or yielding wall, so as to effect a resilient retraction of ring 45a. without departing from the spirit of my invention.

In Figures 6, '1, and 8 I have illustrated a further modication of my invention, and the major difference of this construction over that shown in Figures 4 and 5 resides in the use of a somewhat different means for establishing the resilient or yielding reaction for the accelerationresponsive ring.

With continued reference to these figures, driving plate 1a is provided with an annular groove 1I, in which ring 45h is piloted. Ring 45h is also adapted to engage a circular face 12 of plate 1a. under certain conditions. A plurality of pins 13 lare mounted in ring 45h and extend into elongated recesses 14 in plate 1a., and accordingly limit themovement o'f ring 45hl with respect to plate 1a, to the degree indicated in Figure 8. Recesses 14 in the present instance have been formed in ring 45h by means of a milling cutter, and they accordingly have two inclined portions, one of which is inactive, as will presently appear.

Ring 45h is actuated in response to acceleration of shaft I by a plurality of shouldered pins 15, which are slidably mounted in apertures 16 in reaction plate I3, and extend into elongated curved recesses 11 in ring 45h. As seen in Figure '7, the heads of plungers 15 are flush with the bottoms of the seats in plate I3 for pressure springs I6, and each plunger is disposed under a spring, with the result that each plunger is normally held in the position shown in Figure 1 under a yielding pressure. Plungers 15 are preferably less in number than springs I6, with the result that ring 45h can never be engaged under the full pressure of springs I6 independently of plate 1a. In the present instance plungers 15 are three in number, while six springs I6 are used.

When driving shaft I is given an acceleration, ring 45h manifests a tendency to remain stationary and accordingly moves rearwardly with respect to plate I3 and curved walls of recesses 11 engage plungers 15 and cam ring 45h into engagement with facing I2. After engagement has been effected and the self-energizing action manifests itself, ring 45h is pulled rearwardly to its limit of movement with pins 13 in engagement with the other walls of slots 14. When this occurs, forces of considerable magnitude are applied to plungers 'I5 and they each move to the right as illustrated in Figure 7 against the action ring 45h in this form of the invention are definitely limited by the pressure of the springs I6 with which each plunger cooperates.

With ring 45h engaged with facing I 2as just l described, further acceleration of driving shaft I is effective to cause weights 21 to bring plate 'la into engagement with facing I2 and establish a non-slipping drive between the parts, as previously described, but in this instance face I2 of plate 1a engages ring 45h and causes the latter to engage facing I2 under the centrifugal action of weights 21. Therefore, when plate 'la is engaged with facing I2, ring 45h becomes la part of plate 1a and provides a supplemental clutch engaging area, and if desiredthe previously described forms of the invention may also be designed to function in this manner.

With the clutch fully engaged as just described,

and shaft I is decelerated to the idling speed of the engine, as soon as the clutch pressure has decreased to such a value that slippage takes place between facing I2 and ring #5b and plate la, ring 45h will rock back into the positionillustrated in Figure 7 with stop pins 'I3 disposed in engagement with the other walls of recesses 14. As seen in Figure 8, when ring 45h is disposed in retracted position, each plunger I is disposed in the bottom or in the mid-portion of the recess 11 and each stop pin 13 is disposed in engagement with a wall of recess 14. Therefore,

ring 45h cannot rock in a direction to effect engagement when the driven shaft tends to overrun with respect to the driving shaft. In this instance plate 45h accordingly does not undergo a self-deenergizing action, and the normal tendency of the plates to separate is. relied upon to disengage ring 451; from facing I2. However, if desired a light retracting spring assembly or the like may be provided for urging ring 45h toward engagement with its seat l2 on plate la,`

without departing from the spirit of my invention. Although I have illustrated my invention as being applied to a single plate clutch, i. e. a clutch having a single driven member and two driving members, it will be understood that if desired it may be readily incorporated in clutches having two or more driven members and three or more driving members. Moreover the invention may be used in manually operable clutches and is therefore not to be understood as limited to use with the automatic clutch herein shown.

The invention may be embodied in other specic forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects' as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, andall changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a clutch, driving means, driven means, means for coupling said means, means for establishing a power transmitting connection between said driving and driven means independently of the operation of said coupling means when an acceleration of predetermined magnitude is imparted to said driving means, said'last means being self-operable to `augment its power transmitting action when said driving means vtends to operate at a speed in excess of said driven means, and means for limiting the power transmitting operation of said last-named means.

2. 'I'he clutch described in claim 1, wherein said means for coupling said driving and driven means is applied to a friction clutch having a pressure plate, and wherein said means for establishing power transmitting connection between said driving and driven means comprises an auxiliary plate mounted for limited rotative movement 'with respect vto said pressure plate.

3. In a power transmitting mechanism, a driving element, a driven element, means for establishing a driving connection between said ele-v ments, and means, comprising frictional parts, for transmitting power between said elements independently of the operation of said first-named celeration of predetermined magnitude, said lastnamed Imeans .being operable to establish a yielding engagement pressure between said frictional parts.

4. In a clutch, a pressure plate mounted for rotation and having a frictional surface disposed substantially normal to its axis of rotation, an auxiliary pla operably associated with said pressure plate and having a frictional surface disposed substantially in the plane of the frictional surface of said pressure plate under certain predetermined conditions; means mounting said auxiliary plate for limited rotative movement with respect to said pressure plate; and means for causing said auxiliary plate to 4move axially of', and project beyond the frictional surface of said pressure plate when an 'acceleration of predetermined magnitude is imparted to said member; an auxiliary plate operably associated with said pressure plate and having, a frictional surface disposed substantially in the plane of the frictional surface of said pressure plate under certain predetermined conditions, means for causing said auxiliary plate to move axially of and project beyond the frictional surface of said pressure plate and frictionally cooperate with said driven member when an acceleration of predetermined magnitude is imparted to said pressure plate, and means for establishing a resilient yielding engaging pressure between said auxiliary plate and said driven member whensaid auxiliary plate is projected. f

6. The clutch described in claim 5, wherein said projecting means comprises cam portions provided on said auxiliary plate and which cooperate with yieldable cam faces. l

'1. In a clutch, a pressure plate mounted for movement into and out of engaging and disengaging cooperation with a driven member, an auxiliary plate mounted for limited rotative movement with respect to said pressure plate and adapted to frictionally cooperate with said driven member, and means for causing said auxiliary plate to move intol frictional engagement with said driven member when said pressure plate is accelerated, comprising a plurality of cam pins projecting from said auxiliary plate, and each of which react against resilient inclined faces provided'on a member which is angularly fixed with respect to said pressure plate.

8. In a friction clutch having a pressure plate and a plurality of compression springs urging it towards engaged position, an auxiliary plate mounted for limited rotative movement with respect to said pressure plate, a driven member, means for causing said auxiliary plate to move toward engaging position when an acceleration of predetermined magnitude is imparted to said pressure plate, comprising cam means provided on said auxiliary plate; and means for transmitting forces set up by said cam means to a part only of said compression springs, to establish a yielding engagement pressure between said driven member and said auxiliary plate when the latter undergoes engaging movement in response to acceleration.

9. The olutch described in claim 8; wherein said last-named means comprises a plurality of cam plungers against which said certain coml0 pression springs act.

ROBERT P. LEWIS. 

